The disclosed embodiments of the present invention relate to filtering out blocker signals, and more particularly, to a signal processing apparatus having a frequency-selective circuit with a mixer module implemented for controlling a frequency response of the frequency-selective circuit and related method thereof.
In general, a wireless communication receiver is required to have the capability of detecting weak signals in the desired frequency band. Specifically, the wireless communication receiver is required to detect in-band signals in the presence of very strong out-of-band (OOB) signals (i.e., blocker signals). The most common solution to solving problems caused by very strong blocker signals is to use very high quality factor (Q) bandpass filters at the input of the wireless communication receiver. For example, surface acoustic wave (SAW) filters may be employed to offer the desired attenuation of OOB blocker signals. However, using SAW filters leads to significantly increased cost and circuit board area.
Thus, there is a need for an innovative design which can effectively attenuate or eliminate the unwanted signal components (e.g., the blocker signals) by using a simple circuit architecture.